Answer :
Let:
A = the school student owns a skateboard
B = the school student owns a bicycle
[tex]\begin{gathered} P(A)=0.68 \\ P(B)=0.72 \\ P(A\cap B)=0.61 \\ Therefore: \\ P(A\cup B)=P(A)+P(B)-P(A\cap B) \\ P(A\cup B)=0.68+0.72-0.61 \\ P(A\cup B)=0.79=79\% \end{gathered}[/tex]Answer:
79%